Common sense should rule.

You don't call for a bruise on a toddlers shin. You don't call for bumps on a toddler's head who's just learning to walk. You don't call about a yeast infection with classic and very textbook symptoms. If you don't know what a yeast infection is, or the symptoms of one you defer to someone that does (ie - a pediatrician).

CPS "ladies" aren't qualified to determine such a thing. They are not doctors. It's why if there is an allegation they are required to bring a kiddo to a pediatrician. Skin conditions can manifest in a million different ways as we are all different. It seriously irks me to hear the "CPS lady" said it was like no rash she's ever seen. That matters why?? That doesn't mean anything other than she's obviously not very educated in skin rashes. Any derm doc will tell you, especially in kids, a yeast rash can look 1000 different ways in 1000 different kids.

The exam the little girl will most likely endure as a result of all of this will be pretty traumatic. As will the entire experience for the parents. So although the family will will not necessarily be literally ripped apart, don't at all assume it won't affect them all on many levels and for a very VERY long time.